Reversion, exhaust in the intake runners?

We had a issue with a lifter and we pulled the Intake, noticed a lot of char in the intake runners, way up passed the head, and lightly in the plenum area. Interesting enough, not a lot in the cylinder head side on the intake ports. The char is black just passed the gasket on the intake side, mounting surface.

I am thinking reversion? how do you battle it? I am guessing this is not optimum, and were giving up some ponies.

450 9 degree Darts, wide bore. 30* timing, do not know much about the cam specs. Although with it apart i could put a degree wheel on it if needed.

Thanks, Krom.

Try a shear plate under the carb.

Guessing you cant run these with a titled type spacer?

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Originally Posted by Kromulous

Guessing you cant run these with a titled type spacer?

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Should be able too, they generally only a 1/4" or 3/8" thick as long as the under spacer has large enough holes or is an open spacer but may not be as effective, I'm honestly not sure so.....

When I see streaking on the floor of the intake manifold from the head surface to the plenum it is usually an intake gasket that is failing. It will be a black sticky trail, heavier near the head surface and taper to lighter as it gets to the plenum.

That's kind of what it looks like, heavier where the intake / head split line is. Black, looks like burnt exhaust, not to much in the intake port itself, and light traces in the plenum. We will get it sealed off right, we didnt put it together last time.

I would think an indicator would be if this streaking was just one port or all of them. 1 port would leave me to believe it's localized like a intake gasket or crack and the other would make me think more systemic.

Late model plus fuel?

Not sure what it was run on, we just got it. I will check all the runner when i get back to the shop, as i cant remember if it was all of them, or just one. Maybe even one bank over the other.

The plan is to run Renegade Super Late or whatever its called, i think its 117 and some other fancy stuff in it LOL.

Was told when the engine is on a dyno to hold a timing light over the carburetor, if theres a cloud of fuel you have reversion on work to do. This is with the engine loaded wfo.

http://www.youtube.com/watch?v=7Iq1B-2paCs

Jon is the man and brave too.

Krom, let us know if you try it, lol.

That video is amazing, crazy how much that reversion can pulse. Pretty cool to see just how much fuel is moving thru them ports etc.

So i take it, that true exhaust reversion is when that pulse gets strong enough, that the burnt exhaust charge changes direction and back feeds up thru the intake valve and starts to try and burn the incoming air fuel mixture. Seems really counter productive LOL.